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K Morihara

Publications and source records attributed to K Morihara.

At least 19 recordsLinked to original sources
PubMed2002

Follicular lupus erythematosus: a new cutaneous manifestation of systemic lupus erythematosus.

We report the clinical, histopathological and immunological features of follicular erythema and petechiae in a 30-year-old Japanese woman with systemic lupus erythematosus (SLE). Histology showed this eruption to constitute a cutaneous manifestation of SLE. To our knowledge, this is the first reported case of follicular erythema and petechiae in association with SLE. Accordingly, we propose that this rare eruption be termed 'follicular lupus erythematosus'.

Adult↗
PubMed2000

Use of Bacillus brevis for synthesis and secretion of Des-B30 single-chain human insulin precursor.

A synthetic gene encoding a single chain human insulin precursor [B-chain (1-29)-A-chain] linked to the C-terminal lysine of human epidermal growth factor (1-28) (EGF-SCI) was constructed. This gene was expressed using Bacillus brevis. EGF-SCI was isolated from the supernatant of the culture broth. Treatment of EGF-SCI with lysyl endopeptidase resulted in the formation of des-B30 human insulin. The identification of the formed des-B30 human insulin was made by the measurement of molecular weight and amino acid analysis. The binding coefficient to anti-human insulin antibody was comparable to that of human insulin.

Amino Acid Sequence↗
PubMed2000

Distribution of sarcophytol A in soft coral of the Sarcophyton genus.

The distribution of sarcophytol-A in the Sarcophyton genus was investigated in seven samples belonging to S. glaucum (3 samples), S. infundibulifurme (2 samples), S. crassocaule (1 sample) and S. trocheliophorum (1 sample) that were collected on Ishigaki Island in Okinawa Prefecture. Sarcophytol-A was present in one sample each of S. glaucum and S. infundibulifurme. This study indicates that the composition of cembranoids in the Sarcophyton genus is not related with the respective species, but with the individual samples collected.

Animals↗
PubMed1998

Long-range effect of mutation of calcium binding aspartates [correction of asparates] on the catalytic activity of alkaline protease from Pseudomonas aeruginosa.

Apart from a catalytic domain, the alkaline protease of Pseudomonas aeruginosa has a novel parallel beta-helix domain stabilized through Ca2+ binding. In order to clarify the importance of the beta-helix structure in maturation of the enzyme, aspartic residue D-356 or D-365 in the Ca2+ binding sequence motif was replaced with L-alanine, and the catalytic activity of each mutant was assayed. These mutants did not show any proteolytic activity, although the composition of their polypeptide chains was the same as that of the wild type except for the mutated alanine residue. These results suggest that D-356 and D-365 are important in control of the beta-helix folding induced by Ca2+ binding and that incomplete beta-helix folding due to the lack of their side-chains affects the maturation of the enzyme in the long-range order.

Aspartic Acid↗
PubMed1997

Dissection of the promoter/operator region and evaluation of N-acylhomoserine lactone mediated transcriptional regulation of elastase expression in Pseudomonas aeruginosa.

In Pseudomonas aeruginosa, expression of the lasB gene which codes for the metalloprotease, elastase, depends on small diffusible N-acylhomoserine lactones. lasB expression is regulated through the interactions of N-3-oxododecanoyl-L-homoserine lactone and N-butanoyl-L-homoserine lactone with the transcriptional activators LasR and VsmR(RhlR), respectively. To investigate lasB expression further, we first located the transcriptional start site to a position 141 bp upstream from the translational start site. Using this information, we constructed a series of plasmids containing consecutive 5' deletions of the upstream region of lasB fused to a promoterless chloramphenicol acetyltransferase reporter gene. The results obtained indicate that three regions are required for efficient transcription of lasB; a 35 bp palindromic sequence located at +26 to +60 bp upstream from the translation start site, and two regions located upstream of the transcription start site, at -135 to -85 bp and -63 to -26 bp, respectively. Deletion of the latter region results in the loss of both N-butanoyl-L-homoserine lactone- and N-3-oxododecanoyl-L-homoserine lactone-mediated stimulation of lasB expression and provides further support for the role of this operator site as a target for either or both LasR and VsmR.

Bacterial Proteins↗
PubMed1995

Crystal structure of the unliganded alkaline protease from Pseudomonas aeruginosa IFO3080 and its conformational changes on ligand binding.

The crystal structure of the unliganded alkaline protease from Pseudomonas aeruginosa IFO3080 has been determined at 2.0 A resolution by the X-ray method. The enzyme consists of N-terminal catalytic and C-terminal beta-helix domains. On structural comparison between the present unliganded enzyme and structurally- known liganded enzyme, some structural changes were observed around the active site. In the unliganded enzyme, Y216 serves as the fifth ligand for the active site zinc ion. On ligand binding, Y216 may move to form a hydrogen-bond with the carbonyl oxygen of the P1 residue of a ligand peptide. D191 in the flexible loop, Y190 to D196, over the active site cleft forms hydrogen-bonds with the backbone atoms of the P1 and P2 residues of the ligand to close the entrance to the cleft. The water molecule which is the fourth ligand for the zinc ion is replaced by the carbonyl oxygen of the P1 residue. These structural changes around the active site may reflect the substrate-binding mode during the enzymatic reaction.

Bacterial Proteins↗
PubMed1994

Elastase gene expression in non-elastase-producing Pseudomonas aeruginosa strains using novel shuttle vector systems.

In order to determine whether non-elastase-producing strains of Pseudomonas aeruginosa such as N-10, PA103 and IFO3080 can express foreign elastase genes, we introduced elastase genes from P. aeruginosa IFO3455 (elastase-producing) as well as from PA103 and N-10 into non-elastase-producing P. aeruginosa strains. Results suggested that gene expression, secretion, and precursor processing systems of elastase were essentially normal in P. aeruginosa N-10 and IFO3080. Our studies using various elastase genes showed that both the elastase structural gene and 5'-upstream regions of P. aeruginosa PA103 were also normal. This was confirmed by the finding that P. aeruginosa N-10 and IFO3080 which carry the PA103 elastase gene produced elastase. Several deleted or chimeric genes were constructed using the 5'-upstream regions of elastase genes from P. aeruginosa N-10 or PA103 and studies of expression revealed that two individual DNA bases seem to be important in suppressing P. aeruginosa N-10 elastase gene expression. Possible reasons for the lack of elastase expression in these non-elastase-producing strains are discussed.

Base Sequence↗
PubMed1993

Site-directed mutagenesis of Glu-141 and His-223 in Pseudomonas aeruginosa elastase: catalytic activity, processing, and protective activity of the elastase against Pseudomonas infection.

Both Pseudomonas aeruginosa elastase and Bacillus thermoproteolyticus thermolysin are zinc metalloproteases. On the basis of the high homology of the P. aeruginosa elastase with the Bacillus thermolysin, we hypothesized that Glu-141 and His-223 are the key residues for catalytic activity of the Pseudomonas elastase. To test this possibility, we replaced Glu-141 with Asp, Gln, and Gly and His-223 with Gly, Glu, and Leu by site-directed mutagenesis. These substitutions dramatically diminished the proteolytic activities of the mutant elastases when they were expressed in Escherichia coli cells. Although these mutant elastase precursors (proelastases) were produced, no appreciable processing was observed with these mutants. The possibility that autocatalysis is involved in both the processing and activation of elastase is discussed. Furthermore, by immunizing mice with vaccines made from these mutant elastase, we were able to obtain good protection against an intraperitoneal P. aeruginosa challenge.

Animals↗
PubMed1992

Structural gene and complete amino acid sequence of Vibrio alginolyticus collagenase.

The DNA encoding the collagenase of Vibrio alginolyticus was cloned, and its complete nucleotide sequence was determined. When the cloned gene was ligated to pUC18, the Escherichia coli expression vector, bacteria carrying the gene exhibited both collagenase antigen and collagenase activity. The open reading frame from the ATG initiation codon was 2442 bp in length for the collagenase structural gene. The amino acid sequence, deduced from the nucleotide sequence, revealed that the mature collagenase consists of 739 amino acids with an Mr of 81875. The amino acid sequences of 20 polypeptide fragments were completely identical with the deduced amino acid sequences of the collagenase gene. The amino acid composition predicted from the DNA sequence was similar to the chemically determined composition of purified collagenase reported previously. The analyses of both the DNA and amino acid sequences of the collagenase gene were rigorously performed, but we could not detect any significant sequence similarity to other collagenases.

Amino Acid Sequence↗
PubMed1991

Detection of elastase production in Escherichia coli with the elastase structural gene from several non-elastase-producing strains of Pseudomonas aeruginosa.

The elastase structural gene from Pseudomonas aeruginosa IFO 3455 has been cloned and sequenced. Using this gene as a probe, we cloned the DNA fragments (pEL3080R, pEL10, and pEL103R) of the elastase gene from non-elastase-producing strains (P. aeruginosa IFO 3080, N-10, and PA103 respectively). These three Pseudomonas strains showed no detectable levels of elastase antigenicity by Western blotting (immunoblotting) or by elastase activity. When elastase structural genes about 8 kb in length were cloned into pUC18, an Escherichia coli expression vector, we were able to detect both elastase antigenicity and elastolytic activity in two bacterial clones (E. coli pEL10 and E. coli pEL103R). However, neither elastolytic activity nor elastase antigenicity was detected in the E. coli pEL3080R clone, although elastase mRNA was observed. The partial restriction map determined with several restriction enzymes of these three structural genes corresponded to that of P. aeruginosa IFO 3455. We sequenced the three DNA segments of the elastase gene from non-elastase-producing strains and compared the sequences with those from the elastase-producing P. aeruginosa strains IFO 3455 and PAO1. In P. aeruginosa N-10 and PA103, the sequences were almost identical to those from elastase-producing strains, except for several nucleotide differences. These minor differences may reflect a microheterogeneity of the elastase gene. These results suggest that two of the non-elastase-producing strains have the normal elastase structural gene and that elastase production is repressed by regulation of this gene expression in P. aeruginosa. Possible reasons for the lack of expression in these two strains are offered in this paper. In P. aeruginosa IFO 3080, the sequence had a 1-base deletion in the coding region, which should have caused a frameshift variation in the amino acid sequence. At present, we have no explanation for the abnormal posttransciptional behavior of this strain.

Amino Acid Sequence↗
PubMed1991

Thermolysin catalyzed semisynthesis of peptide hormones by introduction of Phe-NH2 or Tyr-NH2 at the carboxyl termini.

The semisynthesis of C-terminal peptides of gastrin, calcitonin gene-related peptides (rat and human), and cholecystokinin, or of human neuropeptide Y was achieved by introduction of Phe-NH2 or Tyr-NH2 at their carboxyl termini, respectively. Thermolysin or the related enzyme was used for the purpose. The coupling was usually performed in the presence of high concentration of organic cosolvent, where the secondary hydrolysis was negligibly small.

Amino Acid Sequence↗
PubMed1990

Degradation of IgA proteins by Pseudomonas aeruginosa elastase.

Human colostral IgA and myeloma proteins of both IgA1 and IgA2 subclasses were susceptible to cleavage by Pseudomonas aeruginosa elastase. Detailed analysis of the cleavage products of IgA myeloma proteins revealed complete degradation of Fab with no evidence of intact Fab fragments as intermediate cleavage products. In contrast, both IgA1 and IgA2 proteins were resistant to cleavage by alkaline protease from P. aeruginosa. The susceptibility of human IgA proteins to elastase suggests a mechanism by which P. aeruginosa might evade the potentially protective function of IgA by producing this enzyme.

Bacterial Toxins↗
PubMed1990

Molecular cloning and partial DNA sequencing of the collagenase gene of Vibrio alginolyticus.

DNA fragments Vibrio alginolyticus chemovar iophagus, at least 7 kb in length, were ligated to Escherichia coli expression vectors. Three clones of Escherichia coli HB101 (pLCO-1, pLCO-2, pLCO-3) were obtained by the colony immunoblotting method using anti-collagenase antibody. In Escherichia coli, all these genes produced collagenase antigens which were detected with Western blotting. The amino acid sequence of chemically purified collagenase fragments was also analyzed. An approximately 2.5 kb DNA fragment of the pLCO-1 clone was sequenced, and we found that portions of the deduced amino acid sequence of the chemically analyzed fragments. Therefore, it is highly probable that the gene studied in the present experiment is truly a collagenase structural gene.

Amino Acid Sequence↗